I am in the midst of building a PC for gaming, but I cannot decide on whether to purchase a graphics card now (GTX 660 Ti for $230 at Newegg.com) or wait until the Radeon HD 8000 series comes out in the Q1 of 2013, because then the current cards will drop in price and I will most likely purchase a Radeon HD 7950 (3GB and 384-bit!). I hope to purchase a card in the ~$220 range. I hope to play mainly online first-person shooters on max settings with at least an average of 40 FPS on a 1920x1080p monitor. I am not going to overclock, but will SLI/CrossfireX my cards in the future. So would it be best to purchase the 660 Ti now, or wait until the 8000 series of AMD comes out and presumably, I can buy a 7950 at a lower cost than today's prices?
I'd say think how you feel about it. If you want it now no reason to wait. As said prices are not going to fall before Q1/Q2 next year. And 660 Ti for 230 isn't a too bad deal.
Though 7950 really has 3GB and 384-bit which might come handy if you are going to keep that card for next 3 years to come. It will come handy when next consoles roll out and we're going to see larger textures on games.
What I've understood using PhysX wont come free. It taxes graphic performance if horsepower is given to physics calculations.
So I'd say:
1. If you really want better performance now get 660ti for 230
2. If you don't mind waiting try to grap a 7950 deal as it has better memory and is (a bit) faster.